forked from Minki/linux
27ce405039
implement() is setting bytes in LE data stream. In case the data is not aligned to 64bits, it reads past the allocated buffer. It doesn't really change any value there (it's properly bitmasked), but in case that this read past the boundary hits a page boundary, pagefault happens when accessing 64bits of 'x' in implement(), and kernel oopses. This happens much more often when numbered reports are in use, as the initial 8bit skip in the buffer makes the whole process work on values which are not aligned to 64bits. This problem dates back to attempts in 2005 and 2006 to make implement() and extract() as generic as possible, and even back then the problem was realized by Adam Kroperlin, but falsely assumed to be impossible to cause any harm: http://www.mail-archive.com/linux-usb-devel@lists.sourceforge.net/msg47690.html I have made several attempts at fixing it "on the spot" directly in implement(), but the results were horrible; the special casing for processing last 64bit chunk and switching to different math makes it unreadable mess. I therefore took a path to allocate a few bytes more which will never make it into final report, but are there as a cushion for all the 64bit math operations happening in implement() and extract(). All callers of hid_output_report() are converted at the same time to allocate the buffer by newly introduced hid_alloc_report_buf() helper. Bruno noticed that the whole raw_size test can be dropped as well, as hid_alloc_report_buf() makes sure that the buffer is always of a proper size. Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Acked-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk> Signed-off-by: Jiri Kosina <jkosina@suse.cz> |
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| .. | ||
| hid-core.c | ||
| hid-pidff.c | ||
| hid-quirks.c | ||
| hiddev.c | ||
| Kconfig | ||
| Makefile | ||
| usbhid.h | ||
| usbkbd.c | ||
| usbmouse.c | ||